Honestly, I really don't think they'll make another Arkham Deathstroke.
The previous one was fine as it is; with someone like Joker, there's at least a reason to make new figures, because he's had new costumes and variations on his looks, and could use more articulation. Deathstroke has perfect articulation already, and he looks exactly the same as he does from Origins. Even if he looks SLIGHTLY different, it would be on minuscule paint details alone. Getting the Origins Deathstroke fits perfectly with the Knight figures because they're exactly the same. Even Two-Face had a slight remodeling, but I don't see a reason why DC Collectibles would bother with another Deathstroke.
I could see them doing a Firefly, though, his look is different enough.